I am trying to create a bash script to simulate a mail attack to our mailserver. For this reason i want to create a bash script to send hundred of mails to our server, but when i launch the command: $telnet 192.168.12.1 25 <-- where 192.168.12.1 is the ip of our server The telnet session start and all the commands that i write later aren't executed. I also tried to create a second script to launch command on the telnet session after that this one are been created, but when i write from the second script: $echo -ne "EHLO domain.com\r\f" It print the command but doesn't do the ENTER so the command is not taken. Any idea?